Olmec art style was not defined until the mid-20th century.
In addition to an art style, the term “Olmec” is often used to define a civilization.
While Olmec art found in the early urban capitals may be used as evidence for theories of the advent of complex civilization, a significant amount of Olmec art seems to have been found outside these cities, and it is doubtful that provincial objects should be used as evidence for the rise of urbanity without significant corollary relations (see San Lorenzo Fine Ceramics and Mesoamerica for a key case where these matters are tested).
Caso 1942 first attempts a synthesis of the known corpus of art objects, followed by Covarrubias 1946 and Covarrubias 1957.
An enormous number of works treat Olmec art, but few of these focus solely on the art.
Instead, most overviews conflate the art style and the iconography found in the urban capitals to say something about the rise of civilization in the Ancient Americas.
Other objects containing glyphs include the Tuxtla Statuette, the Chiapa de Corzo shard, the O’Boyle mask, and the La Mojarra stela (discovered 1986).
The last object, which displays 465 glyphs, greatly facilitated the interpretation of the epi-Olmec language, though many questions remain.
This has led to some confusion surrounding the term, as noted by numerous scholars.
In many sources, Olmec is shorthand for the civilization that arose in the lowlands of southern Veracruz and Tabasco during the Formative period.